As is generally known in the art, spinal abnormalities may be correctable using a pair of posterior spinal fixation rods attached to the vertebrae using pedicle screws and the like. One such spinal fixation system is described in co-pending, related application Ser. No. 10/915,902 mentioned above.
In order to provide increased stability and rigidity, especially to resist twisting or the like, the pair of elongated rods often includes cross-connecting devices. The cross connecting devices typically traverse the spinal column and couple to each of the elongated rods. In other words, the cross connecting devices are perpendicular or substantially perpendicular to the spinal column.
One difficulty with connecting the elongated rods using cross-connecting devices resides in the fact that the pair of elongated rods is not exactly parallel and equally spaced along the spine. The cross connecting devices typically comprises at least two separate portions that couple together to compensate for these deviations. To couple the separate parts of the cross connecting device together, a coupling device must be provided that has a plurality of degrees of freedom so the cross connecting devices can be rotationally, angularly, and vertically oriented to compensate for the deviations.
While providing separate devices provides a satisfactory solution relating to the coupling the cross connecting devices to the pair of elongated rods, it causes different problems. One such problem, for example, is that the force required to satisfactorily connect to separate devices provides stresses to the cross connecting devices that may cause twisting and bending of the pair of elongated rods. Thus, it would be desirous to develop an improved cross connector that addresses this and other problems associated with the prior art.